JP2001127553A - Inverter piezoelectric oscillation circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inverter piezoelectric oscillation circuit that realizes a low current consumption without decreasing an oscillation loop gain. SOLUTION: The inverter circuit of the inverter piezoelectric oscillation circuit is configured such that the gate of a P-channel MOSFET and the gate of an N-channel MOSFET are interconnected to form a 1st input terminal, a drain of the P-channel MOSFET and the drain of the N-channel MOSFET are connected via a series resistor circuit consisting of at least two resistive elements connected in series, the connecting point of the series resistor circuit is used for an output terminal, the output terminal and the gate of the N-channel MOSFET are connected via a resistive element, the drain of the N-channel MOSFET is used for a 2nd input terminal, the source of the N-channel MOSFET is connected to the ground, and a positive power is supplied to the source of the P-channel MOSFET. Thus, it is possible to suppress the current consumption without decreasing the loop gain of the oscillation circuit so that the low current consumption can be realized while keeping stable oscillation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a piezoelectric oscillation circuit, and more particularly, to an inverter piezoelectric oscillation circuit using an inverter circuit as an amplification circuit.

[0002]

2. Description of the Related Art It is desired that a crystal oscillator used in a portable telephone has low current consumption in order to make a talk time of the portable telephone long. FIG. 3 shows a conventional low current consumption type inverter crystal oscillation circuit. As shown in the figure, an inverter crystal oscillation circuit 100 includes a crystal oscillator 102 inserted and connected between the input and output of an inverter circuit 101.
And load capacitors 103 and 104 inserted and connected between each of the terminals of the crystal unit 102 and the ground.

The inverter circuit 101 includes a gate of a P-channel MOSFET 105 and an N-channel MOSFET.
The gate of the SFET 106 is connected, the drain of the P-channel MOSFET 105 is connected to the drain of the N-channel MOSFET 106, and their connection midpoints are connected via the resistor 107. And furthermore
The power supply Vcc and the source of the P-channel MOSFET 105 are further connected via a resistor 108 to an N-channel MOSFET.
The SFET 106 and the ground are connected via a resistor 109, respectively. Note that Vin shown in FIG.
Represents the input voltage on the gate side of the MOSFET that is the input terminal of the inverter circuit 101, and Vout represents the output voltage on the drain side of the MOSFET that is the output terminal of the inverter circuit 101.

[0004] Such a configuration is a P-channel type MOS.
FET 105 and N-channel MOSFET 106
Are suppressed by the resistor 108 and the resistor 109 when both are in the conductive state. As a result, the current consumption of the inverter crystal oscillation circuit 100 can be reduced. That is, when the input sine wave signal from the crystal unit 102 reaches, for example, the vicinity of the center level of the amplitude, the inverter circuit 101 sets this level as a threshold level.
The channel type MOSFET 105 conducts, and the N-channel type MOSFET 106 does not operate. Therefore, the output Vout is the P-channel MOSFET 10
5 to output the voltage Vcc.

On the other hand, at an input level higher than the threshold level, the P-channel MOSFET 105 becomes non-conductive and the N-channel MOSFET 106 becomes conductive. Therefore, the output Vout outputs the ground voltage 0 V via the N-channel MOSFET 106. By repeating this series of operations, the rectangular waveform clock signal is intermittently output.

In general, near the threshold level, a P-channel MOSFET 105 and an N-channel MOSFET constituting an inverter circuit are provided.
Since T106 and T106 operate at the same time, a through current flows through both FETs at the same time, and as the through current increases, the consumption current of the oscillation circuit increases. Therefore, in the inverter piezoelectric oscillation circuit 100, the resistance 108
By providing the resistor 109 and the resistor 109, the increase in the through current is suppressed, and as a result, low current consumption is realized.

[0007]

However, in the inverter piezoelectric oscillation circuit 100 having the above-described configuration, since the resistors 108 and 109 act as loads on the oscillation loop, the output signal level decreases and the oscillation occurs. Not only did the loop gain of the amplifier circuit decrease, and sufficient oscillation conditions could not be obtained, but in the worst case, the oscillation operation stopped.

It is an object of the present invention to provide a piezoelectric oscillation circuit using a low-current-consumption oscillation circuit by solving the above-mentioned problems of a piezoelectric oscillation circuit using an inverter circuit.

[0009]

According to a first aspect of the present invention, there is provided an inverter piezoelectric oscillation circuit having an inverter circuit and a piezoelectric vibrator. , P-channel type MOSFE
The gate of T and the gate of the N-channel MOSFET are connected to serve as a first input terminal, and the drain of the P-channel MOSFET and the N-channel MOSFET are connected.
The drain of the FET is connected via a series resistance circuit in which at least two resistance elements are connected in series, and a connection point of the series resistance circuit is used as an output terminal, and the terminal and the gate of the N-channel MOSFET are connected. Connected via a resistance element, the drain of the N-channel MOSFET as a second input terminal, the source of the FET grounded,
It is configured to supply a positive power supply to the source of the channel type MOSFET. The piezoelectric vibrator is connected between first and second input terminals of the inverter, and both ends of the piezoelectric vibrator are connected to ground. A first and a second capacitance element are connected therebetween, and the P-channel MOS
A third capacitance element is connected between the drain of the FET and the second input terminal, and a fourth capacitance element is connected between the drain of the P-channel MOSFET and the ground.

According to a second aspect of the present invention, there is provided an inverter piezoelectric oscillation circuit including an inverter circuit and a piezoelectric vibrator, wherein the inverter circuit is a P-channel type MOSFET.
The gate of T and the gate of the N-channel MOSFET are connected to serve as a first input terminal, and the drain of the P-channel MOSFET and the N-channel MOSFET are connected.
The drain of the FET is connected via a series resistance circuit in which at least two resistance elements are connected in series, and a connection point of the series resistance circuit is used as an output terminal, and the terminal and the gate of the P-channel MOSFET are connected. Connected via a resistance element, the drain of the P-channel MOSFET as a second input terminal, the source of the FET grounded,
It is configured to supply a minus power to the source of the channel type MOSFET. The piezoelectric vibrator is connected between the first and second input terminals of the inverter, and both ends of the piezoelectric vibrator are connected to the ground. The first and second capacitive elements are connected between them, and the N-channel type MO is connected.
A third capacitor is connected between the drain of the SFET and the second input terminal, and a fourth capacitor is connected between the drain of the N-channel MOSFET and ground.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. FIG. 1 shows an embodiment of an inverter piezoelectric oscillation circuit according to the present invention. The inverter piezoelectric oscillation circuit 1 shown in FIG.
And load capacitors 4 and 5 inserted and connected between each of the terminals of the crystal unit 3 and the ground.

The inverter circuit 2 has a P-channel type MO.
Drain of SFET 6 and N-channel MOSFET 7
Are connected to, for example, two resistors 8 and 9 having the same resistance value.
, The gates of both MOSFETs are connected to each other, and the midpoint of this connection and the midpoint of the previous series circuit are connected via a resistor 10. The power supply Vcc is connected to the ground of the source of the N-channel MOSFET 7.

The inverter crystal oscillator circuit 1 connects one terminal of the crystal oscillator 3 to the gates of the two MOSFETs, and connects the other terminal of the crystal oscillator 3 to the drain of the N-channel MOSFET 7. Further, P
The drain of the channel type MOSFET 6 is connected to the ground via a capacitor 11, and the drain is connected to the other terminal of the crystal unit 3 via a capacitor 12. When the input signal level is at the threshold level, the inverter piezoelectric oscillation circuit 1 thus configured
The SFET 6 and the N-channel MOSFET 7 function so that an increase in the through current generated due to the operation of both the SFET 6 and the N-channel MOSFET 7 is suppressed by passing through the resistors 8 and 9.

Further, since the inverter crystal oscillation circuit 1 feeds back the AC signal to the oscillation loop via the capacitors 5, 11, and 12 without passing through the resistors 8 and 9, the loss of the signal level fed back is lost. Is reduced. Accordingly, a decrease in the oscillation loop gain is suppressed, so that a stable oscillation operation can be maintained.

FIG. 2 shows another embodiment of the inverter crystal oscillation circuit according to the present invention. The feature of the inverter crystal oscillation circuit shown in FIG. 5 is that the P-channel MOSFET and the N-channel MOSFET of the inverter crystal oscillation circuit shown in FIG. It is configured to connect the ends.

It is clear that even with the inverter crystal oscillator having such a configuration, a function equivalent to the function of the inverter crystal oscillator of FIG. 1 described above can be obtained.
Although the present invention has been described using a quartz oscillator as the piezoelectric vibrator, the present invention is not limited to this, and may be applied to any oscillator using a piezoelectric vibrator.
Furthermore, the resistance 8 and the resistance 9 have been described as having the same resistance value, but the present invention is not limited to this, and the values of the resistance 8 and the resistance 9 are determined based on other circuit conditions and the required output waveform conditions. Needless to say, it may be set as appropriate.

[0017]

As described above, in the inverter piezoelectric oscillation circuit according to the present invention, the resistance circuit for suppressing the increase of the through current is inserted and connected between the drain of the P-channel MOSFET and the N-channel MOSFET. In addition, the drain of the P-channel MOSFET and the other terminal of the crystal unit are connected via a capacitor, so that the lowering of the loop signal level due to the resistor circuit does not occur. It is possible to prevent the loop gain of the circuit from lowering, to maintain a stable oscillation operation, and to reduce the current consumption.

[Brief description of the drawings]

FIG. 1 shows an embodiment of an inverter piezoelectric oscillation circuit according to the present invention.

FIG. 2 shows an embodiment of an inverter piezoelectric oscillation circuit according to the present invention.

FIG. 3 shows a conventional inverter piezoelectric oscillation circuit. 1, 100 inverter crystal oscillation circuit, 2, 101 inverter circuit, 3, 102 crystal oscillator, 4, 5, 11, 12, 103, 104 capacitor, 6, 105 P-channel MOSFET, 7, 106 N-channel MOSFET, 8, 9,10,107,108,109 resistance

Claims (2)

[Claims] 1. An inverter piezoelectric oscillation circuit comprising an inverter circuit and a piezoelectric vibrator, wherein the inverter circuit connects a gate of a P-channel MOSFET and a gate of an N-channel MOSFET and has a first input terminal. And a drain of the P-channel MOSFET and a drain of the N-channel MOSFET are connected via a series resistance circuit in which at least two resistance elements are connected in series, and a connection point of the series resistance circuit is connected to an output terminal. And the terminal and the N-channel MOSFET
And the drain of the N-channel MOSFET is used as a second input terminal.
The source of ET is grounded, and the P-channel MOSFET
T is configured to supply a positive power supply to the source, and the piezoelectric vibrator is connected between the first and second input terminals of the inverter, and between both ends of the piezoelectric vibrator and ground. A first capacitor and a second capacitor are connected, respectively, a third capacitor is connected between the drain of the P-channel MOSFET and the second input terminal, and a drain of the P-channel MOSFET is connected. An inverter piezoelectric oscillation circuit characterized in that a fourth capacitive element is connected between the inverter and a ground. 2. An inverter piezoelectric oscillation circuit comprising an inverter circuit and a piezoelectric vibrator, wherein the inverter circuit connects a gate of a P-channel MOSFET and a gate of an N-channel MOSFET and has a first input terminal. And a drain of the P-channel MOSFET and a drain of the N-channel MOSFET are connected via a series resistance circuit in which at least two resistance elements are connected in series, and a connection point of the series resistance circuit is connected to an output terminal. And the terminal and the P-channel MOSFET
And the drain of the P-channel MOSFET is used as a second input terminal.
The source of ET is grounded, and the N-channel MOSFET
T is configured to supply negative power to the source of the T, the piezoelectric vibrator is connected between the first and second input terminals of the inverter, and between the both ends of the piezoelectric vibrator and ground. The first and second capacitors are connected respectively, and a third capacitor is connected between the drain of the N-channel MOSFET and the second input terminal.
An inverter piezoelectric oscillation circuit, wherein a fourth capacitive element is connected between the drain of the channel type MOSFET and the ground.